Case 5: Tracer Transport in Deep Convection

1. Case 5: Tracer Transport in Deep Convection STERAO-1996 From Dye et al. (2000)

2. Motivation • Convective processing of chemical species is important to • Moving pollutants to upper troposphere • Cleansing the atmosphere (rain out) • Large-scale models produce inconsistent results for convective transport of scalars

3. Emanuel, Stochastic mixing model Standard, CCSM bulk formulation Kain-Fritsch, Plume model Mixing ratio of surface tracer averaged over the TOGA-COARE region as a function of day (December 18 – January 8) and pressure Results From the NCAR CCSM Using Different Convection Parameterizations From Phil Rasch, EGS talk, 2003

4. Motivation • Convective processing of chemical species is important to • Moving pollutants to upper troposphere • Cleansing the atmosphere (rain out) • Large-scale models produce inconsistent results for convective transport of scalars • Convective-scale models produce reasonably represent convective transport

5. Results From the COMMAS Convective Cloud Model Coupled With Chemistry From Skamarock et al. (2000)

6. To improve sub-grid convective transport and wet deposition in large-scale models, multiple convective-scale models can be used to obtain general characteristics of these processes. This intercomparison provides a means to calibrate a variety of convective-scale models coupled with chemistry.

7. Wyoming Nebraska Colorado Chemistry Transport by Deep Convection Simulate the 10 July 1996 STERAO storm.

8. Chemistry Transport by Deep Convection Purpose: Assess the capability of each model to transport chemical species from the boundary layer to the upper troposphere including the entrainment of free tropospheric air. Parameterizations of lightning-produced NOx will also be compared. Primary Species: Ozone (O3) – tracer Carbon monoxide (CO) – tracer Nitrogen oxides (NOx = NO + NO2) – enhanced by lightning Secondary species: Nitric acid (HNO3), hydrogen peroxide (H2O2), and formaldehyde (CH2O) – soluble that depend on the microphysics

9. Initialization Sounding data came from Skamarock et al. (2000) Convection initiated with 3 warm bubbles

10. Initialization of Chemical Species Initial profile MOZART profile Points from aircraft observations

11. Initialization of Chemical Species

12. Requested Output • Peak updraft velocities as a function of time and location • Volume mixing ratios (ppbv) across the anvil for CO, O3, and NOx: • 1 hour into the simulation at ~10 km downwind of the southeasternmost cell (with a SW-NE orientation) • ~½ hour later at ~50 km downwind of the southeasternmost cell (with a N-S orientation) • Vertical cross section of particle concentration, CO, O3, NO, and NOx at ~6000 s and 50-60 km downwind of convective core • Fluxes of air mass, CO and NOx integrated over the anvil

13. Participants • NCAR using WRF with aqueous chemistry (Barth, Kim) • Chien Wang (MIT) • Ann Fridlind (NASA/Ames) • Jean-Pierre Pinty and Celine Mari (Toulouse) • Maud Leriche (U. Blaise-Pascal)

15. Results

16. Peak Updraft and Location

17. Transects

18. Transects

19. Cross sectionsParticles

20. Cross sectionsCO

21. Cross sectionsO3

22. Cross sectionsNOx

23. Anvil Area (106 m2)

24. Mass Flux (kg m-2 s-1)

25. CO (10-5 mol m-2 s-1)

26. NOx (10-8 mol m-2 s-1)

27. Plans • Discuss these results in detail • Address comments already brought up • Discuss future simulations